CAPEC-97
Cryptanalysis
Cryptanalysis is a process of finding weaknesses in cryptographic algorithms and using these weaknesses to decipher the ciphertext without knowing the secret key (instance deduction). Sometimes the weakness is not in the cryptographic algorithm itself, but rather in how it is applied that makes cryptanalysis successful. An attacker may have other goals as well, such as: Total Break (finding the secret key), Global Deduction (finding a functionally equivalent algorithm for encryption and decryption that does not require knowledge of the secret key), Information Deduction (gaining some information about plaintexts or ciphertexts that was not previously known) and Distinguishing Algorithm (the attacker has the ability to distinguish the output of the encryption (ciphertext) from a random permutation of bits).
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Explain the attack pattern CAPEC-97: Cryptanalysis: how it unfolds, what it needs and how to prevent and detect it in my systems. Use https://capec.mitre.org/data/definitions/97.html and https://cve.bz/cve/capec/97?via=ask-ai-copy, which lists recent CVEs with the weaknesses it exploits. Cite the sources.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this attack pattern's id and public links.
How the attack unfolds
Explore
The attacker looks for a way in.
An attacker discovers a weakness in the cryptographic algorithm or a weakness in how it was applied to a particular chunk of plaintext.
Exploit
They carry out the attack.
An attacker leverages the discovered weakness to decrypt, partially decrypt or infer some information about the contents of the encrypted message. All of that is done without knowing the secret key.
Prerequisites
The target software utilizes some sort of cryptographic algorithm.
An underlying weaknesses exists either in the cryptographic algorithm used or in the way that it was applied to a particular chunk of plaintext.
The encryption algorithm is known to the attacker.
An attacker has access to the ciphertext.
Skills required
- High skill
Cryptanalysis generally requires a very significant level of understanding of mathematics and computation.
Resources required
Computing resource requirements will vary based on the complexity of a given cryptanalysis technique. Access to the encryption/decryption routines of the algorithm is also required.
Consequences
| Impact | Affects | Note |
|---|---|---|
| Read Data | Confidentiality | In most cases, if cryptanalysis is successful at all, an adversary will not be able to decrypt the entire message, but instead will only be able to deduce some information about the plaintext. However, that may be sufficient for an adversary, depending on the context of the attack. |
Mitigations
Use proven cryptographic algorithms with recommended key sizes.
Ensure that the algorithms are used properly. That means:
- 1. Not rolling out your own crypto; Use proven algorithms and implementations.
- 2. Choosing initialization vectors with sufficiently random numbers
- 3. Generating key material using good sources of randomness and avoiding known weak keys
- 4. Using proven protocols and their implementations.
- 5. Picking the most appropriate cryptographic algorithm for your usage context and data
Weaknesses it exploits
- CWE-327 Use of a Broken or Risky Cryptographic Algorithm
- CWE-1204 Generation of Weak Initialization Vector (IV)
- CWE-1240 Use of a Cryptographic Primitive with a Risky Implementation
- CWE-1241 Use of Predictable Algorithm in Random Number Generator
- CWE-1279 Cryptographic Operations are Run Before Supporting Units are Ready
Recent CVEs with these weaknesses
- 6.0CVE-2026-112168
The Magistra software uses weak custom encryption, relies on an outdated compression algorithm to protect the database, and contains embedded secrets.
- 6.8CVE-2026-78537
IBM Guardium Key Lifecycle Manager 4.1, 4.1.1, 4.2, 4.2.1, 5.0, and 5.1 could allow a local attacker to obtain sensitive information due to the use of a weak cryptographic algorithm.
- 8.2CVE-2026-118684
MONAI before 1.6.1 contains an insufficient integrity verification vulnerability in check_hash() that silently returns True when hash_val is None, with MD5 as the default hash type. Attackers performing man-in-the-middle or registry compro…
- 6.0CVE-2026-22063
The private keys of eight eMudhra intermediate CA certificates have been compromised. eMudhra revoked the eight affected intermediate certificates on October 18, 2026. While this is not a software vulnerability, CVE-2026-22063 has been ass…
- 9.1CVE-2026-108015
Private keys for eight eMudhra intermediate CA certificates have been compromised https://emudhra.we-have-a-problem.com/ , which impacts certificate trust for outbound network request features of HCL Notes Client. An unauthenticated netw…
- 9.1CVE-2026-108014
Private keys for eight eMudhra intermediate CA certificates have been compromised https://emudhra.we-have-a-problem.com/ , which impacts certificate trust for outbound network request features of HCL Domino Server. An unauthenticated net…
- 9.1CVE-2026-114820
Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: JSSE). Supported versions that are affected are Oracle Java SE: 8u511-b32, 8u511-perf-b32, 11.0.33.0.2, 1…
- 9.1CVE-2026-91403
Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: JSSE). Supported versions that are affected are Oracle Java SE: 8u511, 8u511-perf, 11.0.33, 17.0.21, 21.0…
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Related attack patterns
Examples
A very easy to understand example is a cryptanalysis technique called frequency analysis that can be successf…
A very easy to understand example is a cryptanalysis technique called frequency analysis that can be successfully applied to the very basic classic encryption algorithms that performed mono-alphabetic substitution replacing each letter in the plaintext with its predetermined mapping letter from the same alphabet. This was considered an improvement over a more basic technique that would simply shift all of the letters of the plaintext by some constant number of positions and replace the original letters with the new letter with the resultant alphabet position. While mono-alphabetic substitution ciphers are resilient to blind brute force, they can be broken easily with nothing more than a pen and paper. Frequency analysis uses the fact that natural language is not random and mono-alphabetic substitution does not hide the statistical properties of the natural language. So if the letter "E" in an English language occurs with a certain known frequency (about 12.7%), whatever "E" was substituted with to get to the ciphertext, will occur with the similar frequency. Having this frequency information allows the cryptanalyst to quickly determine the substitutions and decipher the ciphertext. Frequency analysis techniques are not applicable to modern ciphers as they are all resilient to it (unless this is a very bad case of a homegrown encryption algorithm). This example is inapplicable to modern cryptographic ciphers but is here to illustrate a rudimentary example of cryptanalysis.
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